Please help!  I've got the TR82FB45 Motorguide trolling motor.  I got home yesterday adn noticed that the blade was spinning full speed.  I unplugged the power from my  boat deck, waited for a few minutes, and then plugged it back in again.  It started spinning again at full speed.  I turned the variable knob on the side forward and backward, but it stayed running full speed.

Which switch should I change?

I'm sure you may have checked already but just in case, This may sound silly but doesn't it have a constant on switch?  

Here's the thing about the constant on switch - Even if it's stuck in that position, I should be able to adjust the variable speed.  But, it stays running full speed no matter where I turn the dial.

But, thank you for asking - Please don't be shy, remind me of everything because I am at a loss right now!

Is this a brand new trolling motor you just bought or is it a few years old??

It it on High Bypass

if it on high bypass and the switch to turn it on is stuck it would run in only High speed.

if not and its new, return it. I have a MG tour 109 and have not one problem with it. 3 years now.

The trolling motor was purchased in 2004 by the previous boat owner.  The foot button (the one you press when you want to turn the motor on or off as you are moving from spot to spot) is working, I think..  Even though the blade is spinning full speed, the light on top of the motor (the red arrow) ONLY comes on when I push the foot button.  Keep the suggestions coming, I hope to have it fixed this weekend!

Maybe it's possessed?????  

sounds ligh there might be shortin the pedel. Go on MG site and see where the nearest service center is and I would have them look at it. Infact go on mG site and asked them what to do. Tell them exactly what it is doing. They should be able to help. To me it still sounds like the high-bypass is stuck

Maybe it's possessed after all!  I unhooked the variable speed control, the foot button, AND the three way switch adn it still runs nonstop!